How to Plant, Grow, and Care for Phlox
Because there are so many different types of phlox, sunlight requirements vary. Tall garden phlox do best in full sun, while woodland species thrive in partial shade. (See Recommended Varieties, below, for more information!)
In general, phlox prefer soil that is nutrient rich and evenly moist. They do not like to sit in wet soil, however. Use a garden fork or tiller to prepare your garden bed prior to planting. Loosen the soil to about 12 to 15 inches deep, then mix in a 2- to 4-inch layer of compost to improve soil consistency and fertility.
When to Plant Phlox
- Plant phlox in the spring after the threat of frost has passed, or plant in the fall at least a month before your first frost.
How to Plant Phlox
- It is easier to grow phlox from cuttings/transplants than from seeds, although established plants will readily spread by seed in the garden.
- Space plants according to their mature size.
- If you are transplanting a plant from a pot, dig a hole about twice the size of the pot’s diameter and place the plant so that the top of the root ball is even with the soil’s surface. Fill in around the root ball and remember to water it thoroughly.
You just can’t go wrong with phlox! Here are some of the best species and varieties to try:
Low-Growing Phlox
- Creeping phlox or moss phlox (Phlox subulata) is a low-growing species that works excellently as a ground cover. It spreads slowly, growing in mounds that get 4â6 inches thick. The whole plant turns into a carpet of color in spring, when flowers cover every square inch of foliage. This phlox is particularly stunning when allowed to drape over a rock wallâimagine a waterfall of color! Creeping phlox grows best in well-drained soil and partial to full sun.
- âCandy Stripe’ is a popular variety with pink-and-whiteâstriped flowers.
- âEmerald Blue’ produces a sea of lilac-blue flowers (perfect for that waterfall of color!).
Creeping phlox (P. subulata) has needle-shaped leaves and produces a carpet of flowers.
- Phlox stolonifera, which also goes by the common names creeping phlox and moss phlox, is similar to P. subulata in name only. The main differences between it and P. subulata are that its leaves are oval-shaped (rather than needle-shaped) and its flowers are produced on stems that rise 6â10 inches above the foliage (rather than directly on the foliage). It prefers a shadier growing site with rich, evenly-moist soil.
- âSherwood Purple’ is a delicate little phlox with purplish-pink flowers.
- Woodland phlox or blue phlox (Phlox divaricata) is another low-growing species. As its two common names suggest, it prefers partial to full shade and moist, rich soils, and produces bluish flowers in early spring. Like P. stolonifera, its flowers bloom on stems that rise about a foot or so above the creeping foliage.
- âChattahoochee’ and âBlue Moon’ are two great varieties with beautiful blue-to-violet flowers.
Medium-Height Phlox
- Annual phlox or Drummond’s phlox (Phlox drummondii) grows as an annual rather than a perennial, unlike most other phlox species. Annual phlox rarely grows taller than 2 feet in height. Most varieties are not very heat tolerant, but in warmer regions you may find the heat-tolerant varieties for sale. Plant in well-draining soil in a site that gets partial sun and doesn’t stay too wet.
Tall Phlox
- Garden phlox or summer phlox (Phlox paniculata) is the tallest phlox in cultivation and is probably the species that most folks have in their gardens. It grows in clumps that reach between 3 and 5 feet in height and produces panicles of flowers in mid- to late summer. Though tolerant of most lighting, it grows and flowers best in partial to full sun. It has a reputation for being very susceptible to powdery mildew, but resistant varieties are available.
- âDavid’ has bright white flowers and is resistant to powdery mildew.
- âJeana’, another mildew-resistant variety, produces panicles of petite purplish flowersâsimilar in appearance to a butterfly bush.
Other Phlox
The phlox listed above are just a few of the many species out there. Others of interest to gardeners may be Carolina phlox (P. carolina), meadow phlox or spotted phlox (P. maculata), and sand phlox (P. bifida).
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Tall Phlox: In the Fall, I am to cut back the stems to 2-3 " from soil. Then what? What I have now are in pots.....Do I put them undercover to protect from too much rain? thanks
You can trim down the same way and simply move the pots into an unheated garage. Do not water. It goes dormant. The tall type wonât grow as a houseplant.
I'm new to phlox. Planted 2 tall ones and I think bunnies ate on them. Maybe it was user error, too! Can I root the stems if I place them in water (for how long?) and try to replant them later. I do still have the survivors and they're holding on! Thanks!
Hi, Judy,
You might have some luck rooting the stems. Try it. It could take a couple or a few weeks; hard to know. In the spring, you can also divide the existing plants. Each division should have 3 to 5 vigorous with roots attached. Plant them with the crowns an inch or so below the soil surface. To ensure that the remaining plants survive think about âfencingâ them: Get a quart container such as a deli might put potato salad in. Cut off the bottom. See if you can drop the round tube over the plant to ground level. If you can’t, slice the side of the container and then put it around the plant. It might help to deter rabbits.
We hope this helps!
Phlox and Oregon together is ok ?
I have a number of different coloured Phlox, I live in the west of Ireland. I would like to get my white phlox "growing for a few years" which is tall and health to flower in early July, it never does, is there a way to get my white phlox to flower at this time. Thank You.
My plants were beautiful this spring but now they all seem to be dying. I have had them for years and have never seen them do this. Are they getting old? They have had good watering and sun/shade. We did have a late frost but they seemed fine after it. Help I have probable 50 sq.ft. along a walkway and garden walls.
Hi Jane, just reading up on phlox and saw your concern. I purchased a couple of phlox plants today and in researching, I read that your phlox could be doing well for ages and then all of a sudden it seems as there are hardly any flowers being produced. The reason is that it is time to split the phlox up. Once this is done, you will be back to having even more blooms. Hope thats right and answers your question.
I purchased Ortho Grass B Gone to kill the tall grasses growing in my phlox beds....now after reading the entire label I'm concerned that this might kill my phlox plants. Any advice?
I would love to know how to keep the tall wisps of grass out of my creeping phlox, too. Last year, I tried Preen Weed Preventer, but that didn't stop the growth of the grass.
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